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Need help deciding how to replace home HVAC in Raleigh

Hello -

I am trying to find some information on what we need to do to replace our failing residental HVAC system. Here is what is going on - does anyone have any comments or advice?

My wife and I moved to Raleigh, North Carolina nearly three years ago. Our home has a 15 year-old, 3-ton outdoor Trane HVAC unit  the kind that both heats and cools. We replaced the rusted out heat exchanger soon after we moved in, but now the A/C coil has gone out. They are rusting through and freon escapes, causing the coils to ice up.

Our HVAC guy has told us that replacing the entire unit will probably be the best thing for us to do because the cost to replace the coil (and condenser, which we would do at the same time because it is probably going to go soon, too) would be 2/3 or more of the cost of a replacement unit. We finished off the attic and thus added space; we probably need to move up to a 3.5 ton unit (the house now has about 2,250 square feet of living space). From what little I know about SEER, I guess we are looking at a SEER 13 Trane or Lennox unit. We really like our HVAC guy, and as he is a Lennox dealer that may well be what we wind up with. But...

We dont know anything about this stuff. We dont know if we should get (a) just a heat pump or (b) a combination unit or (c) separate units (an A/C unit and a furnace side by side). We dont even know if we can use a heat pump alone in North Carolina, or whether we would have to supplement it with a furnace. Being a bit cautious, we would like to better understand what our options are, and what might be the best choices. (And unfortunately, cost rules out a geothermal heat pump!)

If any of you folks have the time and inclination (not to mention the experience) to comment to us. we woukd relly appreciate hearing what you have to say!

If your temps normally stay above freezing and you don't see snow and your electric costs are low, go with a heat pump replacement. If not, the best config is duel fuel. Furance and HP will give you option of running the HP in spring and fall but going to gas heat as the backup when it realy gets cold out.

Since you have added additional living space to your home, a heat load calc. must be done to determine the correct size equipment needed to heat/cool your house. When replacing the outdoor unit, make sure to change out the coil with a new one to match the new outside unit.

Re: Need help deciding how to replace home HVAC in Raleigh

Originally posted by fredames We really like our HVAC guy, and as he is a Lennox dealer that may well be what we wind up with.

Bingo! Your homework has been done. Just sit back and RELAX. Let your guy make all the decisions for you. Just give him general guidance about your intentions on how long you will be living there, budget limits, etc..

When I was a kid I loved to go squirrel hunting with my dog and a .22 rifle. When I tried to force my dog to hunt a certain area we never did bag as many squirrels as when I just let her follow her own nose. Please don't try and lead your contractor around by the nose.

"And remember my sentimental friend......that a heart is not judged by how much you love, but by how much you are loved by others" - Wizard of Oz.

Steve Wiggins said:
"When I was a kid I loved to go squirrel hunting with my dog and a .22 rifle. When I tried to force my dog to hunt a certain area we never did bag as many squirrels as when I just let her follow her own nose. Please don't try and lead your contractor around by the nose."

Yeah, but then again you didn't pay your dog a few thousand dollars to sniff around, either. I believe that as informed consumers, we will be better able to decide what would fit our house, climate and budget best. Remember what Reagan said once: "Trust, but verify". He was about the most brain dead CEO this country ever had (actually, he was until 2000) but even so he did come up with a few good thoughts.

And don't forget - bingo is gambling. I prefer knowing what is going on so my money is not so much at risk.

Ideally, your contractor of choice should ask you questions do determine what your needs are. They should do a load calc, to ensure that the unit is properly sized. Then they should present you with a system tailored to your specific comfort needs.

There is nothing wrong with an informed comsumer. And as this is a major purchase and investment in your home you should take an active role in it.

I live down the road from Raleigh the heat pump will work fine , dual fuel will work but alot of people on this site do not realize that you are in a mostly gas pak or package unit market due to the fact that you can not get a system under most homes. If you are on natural gas and do not have the room under your home stay with a high seer gas pak. No gas paks are going to save you on your gas bill, all are 80% you will only save on your summer power bill. Now with that said it is lookinglike electricity is not increasing as much as gas so the heat pump may be the way to go for the time being. just wait electricity will eventually catch up. If you have a the room under your home go with a 90plus furnace and heat pump combination, we call these dual fuel systems and you will be happy I am in the process of making my gas furnace that way. You just do not need that many Btu's in our milder weather but is does on occasions get butt kicking cold. As for the room addition it may need a separate unit, only a contractor can determine that for you.

The cost of gas-only heat is really rising, and it's going to continue to outpace the rate at which electric rates are going to rise in the southeast. Our electric rates aren't as strongly affected by oil and natural gas prices as they are in other regions because the vast majority of our electricity comes from coal.

My vote is dual fuel or electric only... leaning toward electric only if the house's electrical service is big enough to support it. Either way, don't skimp on the control system (aka thermostat!).

People swear that dual fuel is the best of both worlds, but you can't get the full efficiency benefit out of a heat pump in a dual fuel configuration because the heat pump can't run at the same time as the gas heat. An all-electric heat pump can run the backup electric heat at the same time as the heat pump- adding just enough electric heat to supplement the heat pump's output. With dual fuel, as soon as the heat pump isn't keeping up, it has to shut down completely and let gas do the whole job.